Positioning for WLANs and other wireless networks

ABSTRACT

Techniques to support positioning for access points and terminals in WLANs and other wireless networks are described. In one aspect, WLAN positioning is supported with Secure User Plane Location (SUPL). A terminal obtains measurements for an access point in a WLAN and/or receives measurements made by the access point for the terminal. The terminal determines WLAN AP information for the access point and/or the terminal based on the measurements and sends the WLAN AP information to a SUPL Location Platform (SLP). The SLP determines a location estimate for the terminal based on the WLAN AP information. In another aspect, the terminal receives supported network information from the SLP. The terminal obtains network measurement information (e.g., measurements) for a radio access network and determines which particular network measurement information to send based on the supported network information. The terminal sends network measurement information permitted by the supported network information to the SLP.

The present application for patent is a Continuation of U.S. patentapplication Ser. No. 11/982,843, entitled “Positioning for WLANs andother wireless networks”, filed Nov. 4, 2007, and claims priority toprovisional U.S. Application Ser. No. 60/856,684, entitled “Support forWLAN Positioning in SUPL,” filed Nov. 4, 2006, and provisional U.S.Application Ser. No. 60/858,320, entitled “Support for WLAN Positioningin SUPL,” filed Nov. 10, 2006, all assigned to the assignee hereof andincorporated herein by reference.

BACKGROUND

I. Field

The present disclosure relates generally to communication, and morespecifically to techniques for performing positioning.

II. Background

Wireless communication networks are widely deployed to provide variouscommunication services such as voice, video, packet data, messaging,broadcast, etc. These wireless networks may be multiple-access networkscapable of supporting communication for multiple users by sharing theavailable network resources. Examples of such multiple-access networksinclude Code Division Multiple Access (CDMA) networks, Time DivisionMultiple Access (TDMA) networks, Frequency Division Multiple Access(FDMA) networks, and Orthogonal FDMA (OFDMA) networks.

It is often desirable, and sometimes necessary, to know the location ofa terminal in a wireless network. The terms “location” and “position”are synonymous and are used interchangeably herein. For example, a usermay utilize the terminal to browse through a website and may click onlocation sensitive content. The location of the terminal may then bedetermined and used to provide appropriate content to the user. Thereare many other scenarios in which knowledge of the location of theterminal is useful or necessary.

Some wireless networks such as CDMA networks can readily supportpositioning. These wireless networks may have many base stations thattransmit signals encoded with timing information. The location of aterminal may be determined based on timing measurements for a sufficientnumber of base stations and known fixed locations of these basestations. In some wireless networks, the locations of the transmittersmay not be known or there may be uncertainty in the transmitterlocations. Nevertheless, it may be desirable to determine the locationof a terminal in such a wireless network.

SUMMARY

Techniques to support positioning for access points and terminals inwireless local area networks (WLANs) as well as other wireless networksare described herein. Positioning refers to a process to measure/computea geographic location estimate of a target device. WLAN positioningrefers to positioning based on measurements and/or other information forone or more stations in a WLAN. A station may be a terminal or an accesspoint. A location estimate may also be referred to as a positionestimate, a position fix, etc.

In one aspect, WLAN positioning is supported with Secure User PlaneLocation (SUPL) from Open Mobile Alliance (OMA). A terminal, which maybe referred to as a SUPL Enabled Terminal (SET), may obtain measurementsfor signal strength, signal-to-noise ratio (S/N), round trip delay(RTD), and/or some other quantity for an access point in a WLAN.Alternatively or additionally, the terminal may receive measurements forsignal strength, S/N, and/or some other quantity, which may be made bythe access point for the terminal. The terminal may determine WLAN APinformation for the access point and/or the terminal based on themeasurements and may send the WLAN AP information to a SUPL LocationPlatform (SLP), which is a location server in SUPL. The SLP maydetermine location information (e.g., a location estimate) for theterminal based on the WLAN AP information and may send the locationinformation to a requesting entity.

In another aspect, positioning in SUPL is supported using supportednetwork information. A terminal may receive supported networkinformation from an SLP. The supported network information may informthe terminal of which type(s) of network measurement information aresupported by the SLP. The terminal may obtain network measurementinformation (e.g., measurements for signal strength, S/N, RTD, etc.) fora radio access network (e.g., WLAN, GSM, CDMA, WCDMA, etc.). Theterminal may determine which particular network measurement informationto send to the SLP based on the supported network information. Theterminal may then send network measurement information permitted by thesupported network information to the SLP. The SLP may determine locationinformation (e.g., a location estimate) for the terminal based on thenetwork measurement information received from the terminal.

Various aspects and features of the disclosure are described in furtherdetail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a WLAN that supports positioning.

FIGS. 2A and 2B show positioning of an access point.

FIG. 3 shows OTD measurement by a terminal for two access points.

FIG. 4 shows TOA measurements by two terminals for an access point.

FIG. 5 shows a deployment with user plane location.

FIGS. 6A and 6B show message flows for network-initiated andSET-initiated location services in SUPL with WLAN positioning.

FIG. 7 shows a process performed by a terminal for WLAN positioning inSUPL.

FIG. 8 shows a process performed by an SLP to support WLAN positioningin SUPL.

FIG. 9 shows a network deployment with different radio access networks.

FIGS. 10A and 10B show message flows for network-initiated andSET-initiated location services in SUPL with supported networkinformation.

FIG. 11 shows a process performed by a terminal for positioning in SUPL.

FIG. 12 shows a process performed by an SLP to support positioning inSUPL.

FIG. 13 shows an access point, a terminal, and a network server.

DETAILED DESCRIPTION

Techniques for supporting positioning in wireless networks are describedherein. The techniques may be used for various wireless networks such asWLANs, wireless wide area networks (WWANs), metropolitan area networks(WMANs), broadcast networks, etc. The terms “network” and “system” areoften used interchangeably. A WWAN is a wireless network that providescommunication coverage for a large geographic area such as, e.g., acity, a state, or an entire country. A WWAN may be a cellular networksuch as a CDMA network, a TDMA network, an FDMA network, an OFDMAnetwork, etc. A CDMA network may implement a radio technology such asWideband CDMA (WCDMA), cdma2000, etc. cdma2000 covers IS-2000, IS-95,and IS-856 standards and is commonly referred to as “CDMA”. A TDMAnetwork may implement a radio technology such as Global System forMobile Communications (GSM), Digital Advanced Mobile Phone System(D-AMPS), etc. D-AMPS covers IS-248 and IS-54. These various radiotechnologies and standards are known in the art. WCDMA and GSM aredescribed in documents from an organization named “3rd GenerationPartnership Project” (3GPP). cdma2000 is described in documents from anorganization named “3rd Generation Partnership Project 2” (3GPP2). 3GPPand 3GPP2 documents are publicly available.

A WLAN is a wireless network that provides communication coverage for asmall or medium geographic area such as, e.g., a building, a mall, acoffee shop, an airport terminal, a school, hospital etc. A WLAN mayimplement a radio technology such as any defined by IEEE 802.11,Hiperlan, etc. A WMAN may implement a radio technology such as anydefined by IEEE 802.16. IEEE 802.11 and IEEE 802.16 are two families ofstandards from The Institute of Electrical and Electronics Engineers(IEEE). The IEEE 802.11 family includes 802.11a, 802.11b, 802.11g and802.11n standards and is commonly referred to as Wi-Fi. Each IEEE 802.11standard specifies operation in a specific frequency band (e.g., 2.4 GHzor 5 GHz) using one or more modulation techniques. The IEEE 802.16family includes 802.16e standard and is commonly referred to as WiMAX.Hiperlan is a WLAN technology that is commonly used in Europe. Forclarity, much of the following description is for a WLAN.

FIG. 1 shows a WLAN 100 that supports positioning. WLAN 100 includesaccess points (AP) 110 that communicate with terminals 120. An accesspoint is a station that supports communication for terminals associatedwith that access point. An access point may also be referred to as abase station. For WMAN and WWAN wireless technologies, an access pointmay be replaced by a Node B, an evolved Node B (eNode B), a basetransceiver subsystem, etc. Access points 110 may directly or indirectlycouple to a network server 130 that may perform various functions forpositioning. Network server 130 may be a single network entity or acollection of network entities. In general, a WLAN may include anynumber of access points. Each access point may be identified by anaccess point identity (AP ID), which may be a globally unique MediumAccess Control (MAC) address that is included in frames transmitted bythe access point, an Internet Protocol (IP) address, etc.

A terminal is a station that can communicate with another station via awireless medium. A terminal may be stationary or mobile and may also bereferred to as a mobile station, a user equipment, a subscriber station,etc. A terminal may be a cellular phone, a personal digital assistant(PDA), a handheld device, a wireless device, a laptop computer, awireless modem, a cordless phone, a telemetry device, a tracking device,etc.

An access point or a terminal may also receive signals from satellites140, which may be part of the United States Global Positioning System(GPS), the European Galileo system, the Russian Glonass system, or someother satellite positioning system (SPS). A terminal may measure signalsfrom access points 110 and/or signals from satellites 140. Themeasurements may be used to determine the location of the terminaland/or access points, as described below.

In general, a WLAN and/or its associated terminals may support anynumber of positioning methods and any positioning method. Table 1 listssome positioning methods that may be supported by a WLAN and/or itsassociated terminals and provides a short description for each method.

TABLE 1 Positioning Method Description AP ID Solution based onidentities of access points. RTD Solution based on round trip delay(RTD) measurements. OTD Solution based on observed time difference (OTD)measurements. TOA Solution based on time of arrival (TOA) measurements.Signal strength/ Solution based on signal strength and/or signal qualityquality measurements. Cell ID for A-GPS Solution based on cell ID andused for assisted GPS (A-GPS).

In the following description, the term “GPS” generically refers topositioning based on any satellite positioning system, e.g., GPS,Galileo, etc. The term “A-GPS” generically refers to positioning basedon any satellite positioning system with GPS assistance data.

The positioning methods may be used to (a) determine the locations ofterminals based on known locations of access points and/or (b) determinethe locations of access points based on known locations of terminals.The known locations may be obtained independently with GPS, A-GPS, etc.The ability to determine access point locations based on terminallocations may be highly desirable since numerous WLANs are currentlydeployed, WLANs are not always publicly known, and access points may bemoved (i.e., are not always fixed). The locations of access points maybe determined and/or updated based on terminals supporting independentpositioning methods such as GPS, A-GPS, etc. The access point locationsmay be used to determine the locations of terminals that do not supportindependent positioning methods such as GPS, A-GPS, etc.

The various positioning methods may be supported by the terminals and/orby employing a network server, e.g., network server 130 in FIG. 1 or anyone of access points 110. The network server may instruct the terminalsto provide measurements and may compute location estimates for theterminals and/or access points. The network server may also storelocation information for the terminals and/or access points and may usethe location information to support positioning.

The AP ID method utilizes known locations of access points in a WLAN todetermine the locations of terminals. A location may be given by2-dimensional (x, y) or 3-dimensional (x, y, z) geographic coordinates.The locations of the access points may be determined in various manners.In one scheme, the location of an access point may be determined by aWLAN operator by surveying, using map association, etc. In anotherscheme, the location of an access point may be determined based on apositioning method such as GPS, A-GPS, etc.

FIG. 2A shows a scheme for positioning an access point based on knownlocations of one or more terminals communicating with the access point.A coverage area for the access point may be determined based on theknown locations of different terminals and/or different known locationsof the same terminals. The location of the access point may bedetermined based on all known terminal locations, e.g., an averagelatitude (x) coordinate and an average longitude (y) coordinate for theterminal locations. To avoid bias due to greater density of terminals inone area than other areas, the perimeter of the coverage area may bedetermined based on the outermost terminal locations. The location ofthe access point may then be given by a point within the area enclosedby the perimeter, e.g., the centroid of the enclosed area.

FIG. 2B shows a scheme for positioning an access point based on knownlocation of a single terminal. The location of the terminal may beprovided as an approximate location of the access point. Thisapproximate location has an error or uncertainty that is dependent onthe coverage range of the access point. If the WLAN technology is known(e.g., 802.11b, 802.11g, etc.), then the maximum distance from theterminal to the access point may be estimated based on the rangelimitation of the WLAN technology. For example, many 802.11 technologiesgenerally have range limits of around 50 to 100 meters. The location ofthe access point may then be approximated by the terminal location withthe actual access point location lying within a circle centered at theterminal location and having a radius given by the range limit. Therange limit is typically given for the maximum transmit power allowed bythe WLAN technology. Hence, a smaller radius (and thus less uncertainty)may be used for the circle if it is known that the access point or theterminal used less than the maximum transmit power for communication.

In general, the location of an access point may be determined in advance(e.g., through cartography or surveying) or in the field by applying anyof the positioning methods in reverse. In particular, the access pointlocation may be determined based on one or more known locations of oneor more terminals supporting reliable and accurate positioning methodssuch as GPS, A-GPS, etc.

The AP ID method can provide a location estimate for a terminal based onan identity of an access point serving or received by the terminal andthe known location of the access point. The location of the access pointmay be provided as the location estimate for the terminal. This locationestimate has an uncertainty determined by the coverage range of theaccess point, which may be estimated based on the WLAN technology asdescribed above. The accuracy of the location estimate may then bedependent on the range limit of the WLAN technology. The locationestimate may be fairly accurate for WLAN technologies with limitedcoverage (e.g., up to 50 meters for some IEEE 802.11 technologies) andless accurate for WLAN, WMAN and WWAN technologies with extended rangeor where repeaters are used to extend coverage.

The location of an access point may be made available to terminalswithin the coverage area and/or in other networks. For example, in anIEEE 802.11 WLAN, the access point may include its location in a beaconthat is broadcast periodically to the terminals. In this case, terminalsthat can receive the beacon may be able to estimate their locationsbased on the access point location obtained from the beacon.

The RTD method provides a location estimate for a station based on RTDmeasurements for one or more other stations and known locations of theother stations. For example, a terminal may measure the RTD of radiosignal propagation between the terminal and one or more access points.The location of the terminal may then be determined based on the RTDmeasurements and known locations of the access points usingtriangulation techniques.

RTD measurements may be made in various manners. For example, in IEEE802.11v, a terminal may send a message (e.g., a Presence Request frame)to an access point and may receive an acknowledgment (e.g., a PresenceResponse frame) from the access point. The acknowledgment may containthe time delay measured by the access point between the receive time ofthe last part (e.g., the final bit or chip) of the terminal's messageand the transmit time of the first part (e.g., the first bit or chip) ofthe acknowledgment. The terminal may measure the time delay between thetransmit time of the last part of the message and the receive time ofthe first part of the acknowledgment. The terminal may then subtract thetime delay reported by the access point from the time delay measured bythe terminal to obtain a measurement of RTD. Other schemes may also beused to measure the time difference between sending a given message andreceiving a response.

The OTD method provides a location estimate for a station based on OTDmeasurements for other stations and known locations of the otherstations. For example, a terminal may measure the observed transmissiontiming difference between pairs of access points. These measurements maybe based on transmissions containing implicit or explicit timinginformation from the access points. These transmissions may correspondto beacon frames broadcast periodically by access points in IEEE 802.11WLAN. The location of the terminal may then be obtained based on thesemeasurements using trilateration.

FIG. 3 shows OTD measurement by a terminal i for two access points P andQ. Each access point transmits a series of transmission sequences, e.g.,sequences of binary encoded data. Each transmission sequence containsimplicit or explicit relative time reference. Access points P and Q maytransmit their transmission sequences periodically. For example, eachtransmission sequence may correspond to a beacon frame in IEEE 802.11.Each transmission sequence contains a marker that may be used as a timereference. Terminal i receives two transmission sequences from accesspoints P and Q and identifies the markers in the received transmissionsequences. Terminal i measures the difference between the arrival timeof marker M_(Pi) from access point P and the arrival time of markerM_(Qi) from access point Q. This arrival time difference is denoted asOTD_(i). The location of terminal i may be determined based on OTDmeasurements for two or more pairs of access points with knownlocations. The location of an access point may also be determined basedon OTD measurements from terminals with known locations.

A network server, e.g., network server 130 in FIG. 1, may instruct aterminal to make OTD measurements and may receive the measurements fromthe terminal. The network server may perform location-relatedcomputations to solve for the terminal locations and/or access pointlocations using OTD measurements.

The OTD method may be used for any WLAN technology that sends implicitor explicit timing-related information. The timing-related informationmay be provided via repeated frame structures, repeated frames, otheridentifiable information containing a counter or timing-related data,etc. The OTD method may be similar to an Enhanced Observed TimeDifference (E-OTD) method for GSM networks, an Observed Time Differenceof Arrival (OTDOA) method for WCDMA networks, and an Advanced ForwardLink Trilateration (A-FLT) method for CDMA networks. The E-OTD, OTDOAand A-FLT methods only determine the locations of terminals and rely onhaving knowledge of the locations of base stations. In contrast, the OTDmethod can determine the locations of terminals as well as access pointsand may be used for WLAN as well as other wireless networks, e.g., GSM,WCDMA, and CDMA networks.

The TOA method provides a location estimate for a station based on TOAmeasurements for one or more other stations and known locations of theother stations. For example, a terminal may measure the time of arrivalfor a marker from each of multiple access points and may associateabsolute time with each marker. The terminal may obtain absolute timeusing, e.g., GPS, A-GPS, etc. The location of the terminal may then beobtained based on the measurements using trilateration.

FIG. 4 shows TOA measurements by two terminals i and k at differentlocations for one access point P. Access point P transmits a series oftransmission sequences, with each transmission sequence having a marker.Terminal i receives a transmission sequence from access point P. Themarker in the sequence received by terminal i is denoted as M_(Pi).Terminal j receives a transmission sequence from access point P. Themarker in the sequence received by terminal j is denoted as M_(Pj).Marker M_(Pi) may be the same as or different from marker M_(Pj). Eachterminal m, for m=i or j, may determine an absolute arrival timeA(M_(Pm)) of marker M_(Pm) received by that terminal from access point Pbased on the terminal's knowledge of absolute time. A(M_(Pm)) representsthe TOA measurement made by terminal m for access point P.

The OTD between the absolute arrival time of marker M_(Pi) at terminal iand the absolute arrival time of marker M_(Pj) at terminal j is denotedas OTD_(ij). Three TOA measurements by three different terminals atdifferent known locations may be used to form two equations (with oneterminal common to both equations), which may then be used to determinethe two unknown variables for the x, y coordinates of access point P.Three TOA measurements by a single terminal at different known locationsmay also be used to determine the x, y coordinates of the access point.The locations of access points determined based on the TOA method may beused to determine the locations of terminals using the RTD, OTD, TOA, orother positioning methods. The location of a terminal may also bedetermined using known locations of access points. In this case, threeor more access points obtain absolute TOA measurements for transmissionmarkers transmitted by the terminal.

A network server, e.g., network server 130 in FIG. 1, may instructterminals and/or access points to perform TOA measurements and mayreceive the measurements from the terminals and/or access points. Thenetwork server may then perform location-related computations todetermine the locations of the terminals and/or access points.

The signal strength/quality method provides a location estimate for astation based on signal strength and/or signal quality measurements forone or more other stations and known locations of the other stations.The location of the station may be determined using pattern matching, asdescribed below.

A terminal may record the identities of all access points that can bereceived by the terminal at a particular location. The terminal may alsomeasure the signal strength and/or signal quality for each access pointreceived by the terminal. Signal strength may be quantified by receivedpower and may be given in units of dBm. Signal quality may be quantifiedby signal-to-noise ratio (S/N), energy-per-bit-to-total-noise ratio(Eb/No), bit error rate (BER), packet error rate (PER), observedsignaling errors, etc. Signal quality may be given by a binary valuethat indicates whether or not the signal quality is above a giventhreshold, e.g., whether the signal quality is sufficient to decode theAP identity. The location of the terminal may also be obtained usingindependent means, e.g., GPS, A-GPS, etc. The terminal may report itslocation, the identities of the received access points, and the signalstrength/quality measurement for each access point.

A network server, e.g., network server 130 in FIG. 1, may receivereports from different terminals and/or reports from the same terminalsat different locations. The network server may build up a database ofaccess points received at different locations and the associated signalstrengths/qualities. A geographic area of interest may be partitionedinto small regions or pixels. The regions may have any shape (e.g.,squares, rectangles, hexagons, etc.) and may also have any size (e.g.,few meters across). The location reported by a terminal may be mapped toa single pixel (e.g., the pixel containing the terminal locationcoordinates) or to a small set of pixels (e.g., pixels included in aprobable area in which the terminal is located). The access pointidentities and signal strengths/qualities may be associated with thepixel(s) to which the terminal location is mapped. If reports areobtained from multiple terminals for the same pixel or set of pixels,then the measurements in these reports may be combined (e.g., averaged),and the combined measurements may be stored for the pixel(s). Forexample, signal strengths may be averaged using a moving weighted timeaverage, where the weights may depend on the probability that a giventerminal location is correctly mapped to a particular pixel. Signalqualities may also be averaged. For example, if one signal qualitythreshold is used, then the overall signal quality may relate to thepercentage of terminals for which the threshold was exceeded.

The database may be used for positioning of terminals. The networkserver may obtain from a terminal the identities of access pointsreceived by the terminal and possibly signal strengths/qualities forthese access points. The network server may search the database forpixels marked with the reported access point identities. The networkserver may look for partial pattern matches for the access pointsidentified by the terminal and may ignore access points not identified.The network server may then identify pixels associated with averagedsignal strengths/qualities that most closely match the reported signalstrengths/qualities. The network server may take into account the factthat the sensitivity of different terminals may vary. The result of thesearch may be a set of pixels, not necessarily contiguous, representingpossible locations for the terminal together with the probability thateach pixel was in fact the correct location. The network server mayderive a single location estimate that minimizes the expected locationerror (or the root mean square of the error).

The network server may instruct terminals to obtain signalstrength/quality measurements and may receive the measurements fromthese terminals. The network server may build up and/or update thedatabase and perform location-related computations to determine thelocations of terminals.

The A-GPS method provides GPS assistance data to terminals to assist theterminals acquire and measure GPS signals and/or to compute locationestimates from the resultant measurements. GPS assistance data may alsobe used to support positioning with other satellite positioning systemssuch as the European Galileo system. An approximate location of aterminal is typically needed in order to provide appropriate GPSassistance data to the terminal. For example, knowledge of the terminallocation to within few kilometers is needed to provide acquisitionassistance data and GPS-GSM or GPS-WCDMA timing assistance data used tosupport A-GPS in GSM and WCDMA networks. Any of the positioning methodsdescribed herein may be used to determine the location of the terminalwith the required level of accuracy.

For a cell ID method, a terminal obtains globally unique identities ofone or more cells in a cellular network such as a GSM, WCDMA, or CDMAnetwork. An access point serving the terminal or a network serving theterminal via the WLAN may also provide the terminal with identities ofcells with coverage in the terminal's location. A cell identity may bemapped to a specific location within a cell, e.g., the location of thecell site antenna. This cell location may be provided as a coarselocation estimate for terminals within the cell. The location estimatehas an error determined by the size of the cell.

The location of a station (e.g., a terminal or an access point) may bedetermined using multiple positioning methods. A more accurate andreliable location estimate may be obtained for the station by combininglocation results from these multiple positioning methods. For the signalstrength/quality method, the location result may be a set of possiblelocations (e.g., pixels), each with an associated probability ofoccurrence. For the RTD, OTD and TOA methods as well as the GPS andA-GPS methods, the result may be a single location with a surroundingarea (e.g., a circle or ellipse) within which the actual location isexpected with a particular probability. Each location result may beconverted to a probability density function (PDF) that provides, foreach possible location, the probability that the station is actually atthat location. The probability density functions for all positioningmethods may be combined and used to obtain a final location estimate forthe station.

A network server may obtain from a terminal several sets of measurementsfor different positioning methods such as, e.g., A-GPS, RTD, OTD, TOA,signal strength/quality, etc. The network server may performlocation-related computations for each positioning method and maycombine the results for all positioning methods into more accuratelocation information as described above.

The positioning methods in Table 1 are described in further detail incommonly assigned U.S. patent application Ser. No. 11/557,451, entitled“POSITIONING FOR WLANS AND OTHER WIRELESS NETWORKS,” filed Nov. 7, 2006.

The positioning methods described herein may be supported by terminals,access points, and/or other network entities associated with a WLAN.Positioning for a terminal may occur locally. An entity may request theterminal location from the terminal or the WLAN, e.g., the access point.

It may be more efficient to support positioning of terminals in WLANs byextending existing capabilities of wireless user plane locationsolutions such as SUPL and 3GPP2 X.S0024. The user plane locationsolutions may be used to support positioning for terminals, store andprovide location results, support privacy for a terminal user, supportauthentication of an entity requesting a terminal location, etc. Theuser plane location solutions currently support a number of positioningmethods such as cell ID with timing advance, E-OTD, OTDOA, and A-FLT,which are applicable to WWANs (e.g., GSM, WCDMA, and CDMA networks) butnot WLANs. The user plane location solutions also support otherpositioning methods such as GPS and A-GPS, which are applicable tovarious wireless networks where specialized WLAN support is not needed.The user plane location solutions may be enhanced to support positioningmethods for WLAN.

FIG. 5 shows a deployment with SUPL and X.S0024. A terminal 120 may useWLAN 100 to access the Internet 510, an IP Multimedia Subsystem (IMS)network 520 in 3GPP or 3GPP2, or other 3GPP or 3GPP2 services asdescribed in 3GPP TS 23.234 and 3GPP2 X.P0028. Terminal 120 maycommunicate with WLAN 100, which may be used as a Generic Access Network(GAN) to support access to GSM and GPRS as described in 3GPP TS 43.318.Terminal 120 may use WLAN positioning methods within SUPL or X.S0024when communicating with WLAN 100. In SUPL, a terminal is referred to asa SUPL Enabled Terminal (SET). The terms “terminal” and “SET” are usedinterchangeably below.

SUPL utilizes a SUPL Location Platform (SLP) 530 that is responsible forSUPL service management and positioning. SLP 530 may be a Home SLP(H-SLP), a Visited SLP (V-SLP), an Emergency SLP (E-SLP), etc. SUPLservice management may include managing locations of SETs and storing,extracting, and modifying location information of target SETs. SLP 530includes a SUPL Location Center (SLC) 532 and may include a SUPLPositioning Center (SPC) 534. SLC 532 performs various functions forlocation services, coordinates the operation of SUPL, and interacts withSETs over user plane bearer. SLC 532 may perform functions for privacy,initiation, security, roaming support, charging/billing, servicemanagement, position calculation, etc. SPC 534 supports positioning forSETs, is responsible for messages and procedures used for positioncalculation, and supports delivery of assistance data to the SETs. SPC534 may perform functions for security, assistance data delivery,reference retrieval, position calculation, etc. SPC 534 has access toGPS receivers (a reference network, perhaps a global one) and receivessignals for satellites so that it can provide assistance data.

A SUPL agent 550 may communicate with SLP 530 to obtain locationinformation for terminal/SET 120. A SUPL agent is a service access pointthat accesses network resources to obtain location information. Locationinformation may comprise a location estimate and/or any informationrelated to location. SET 120 may also have a SUPL agent that is residentwithin the SET. SUPL Version 2.0 (SUPL 2.0) is described inOMA-AD-SUPL-V2, entitled “Secure User Plane Location Architecture,” Aug.31, 2007, and OMA-TS-ULP-V2, entitled “UserPlane Location Protocol,”Sep. 27, 2007. These SUPL documents are publicly available from OMA.

X.S0024 utilizes location entities 540 that may include an X.S0024Position Server (PS) 542 and an X.S0024 Position Determining Entity(PDE) 544. PS 542 may perform functions similar to those performed bySLC 532. PDE 544 may perform functions similar to those performed by SPC534.

FIG. 6A shows a design of a message flow 600 for network-initiatedlocation services in SUPL with WLAN positioning. SUPL agent 550 maydesire location information for SET 120 and may send a Mobile LocationProtocol (MLP) Standard Location Immediate Request (SLIR) message to SLP530 (step A). SLP 530 may authenticate and authorize SUPL agent 550 forthe requested location information. SLP 530 may then obtain routinginformation for SET 120 (step B).

SLP 530 may send a SUPL INIT message to initiate a location session withSET 120 (step C). The SUPL INIT message may include a session-id used toidentify the location session, an intended positioning method, thedesired quality of positioning (QoP), etc. Upon receiving the SUPL INITmessage, SET 120 may perform a data connection setup procedure, attachitself to a packet data network if the SET is not already attached, andestablish a secure IP connection to SLP 530 (step D).

SET 120 may then obtain WLAN AP information. In general, WLAN APinformation may include any information for an access point and/or aterminal that may be pertinent for positioning of the terminal. Forexample, the WLAN AP information may comprise parameters of an accesspoint, e.g., an AP ID (MAC address) and a number of optional WLANassociated measurements defined according to IEEE 802.11v, whichprovides positioning support for all IEEE 802.11 radio technologies. SET120 may then send a SUPL POS INIT message to SLP 530 (step F). The SUPLPOS INIT message may include the session-id, the WLAN AP information,and possibly other information such as the SET capabilities (e.g.,supported positioning methods and protocols), request for assistancedata, etc. SLP 530 may determine a location estimate for SET 120 basedon the WLAN AP information (step G). If the location estimate obtainedfrom the WLAN AP information is of sufficient quality, then SLP 530 maysend a SUPL END message to SET 120 (step I) and may send the requestedlocation information in an MLP Standard Location Immediate Answer (SLIA)message to SUPL agent 550 (step J).

If a location estimate of sufficient quality is not obtained based onthe WLAN AP information, then SLP 530 and SET 120 may exchange messagesfor a positioning session (step H). For SET-assisted positioning, SLP530 may calculate a location estimate for SET 120 based on positioningmeasurements received from the SET. For SET-based positioning, SET 120may calculate the location estimate based on assistance obtained fromSLP 530. In any case, upon completing the positioning session, SLP 530may send a SUPL END message to SET 120 (step I) and may also send therequested location information to SUPL agent 550 (step J).

FIG. 6B shows a design of a message flow 610 for SET-initiated locationservices in SUPL with WLAN positioning. A SUPL agent on SET 120 mayreceive a request for location information from an application runningon the SET. SET 120 may perform a data connection setup procedure,attach itself to a packet data network if necessary, and establish asecure IP connection to SLP 530 (step A). SET 120 may then send a SUPLSTART message to initiate a location session with SLP 530 (step B). TheSUPL START message may include a session-id, the SET capabilities, etc.SLP 530 may determine that SET 120 is currently not roaming for SUPL(step C). SLP 530 may then send to SET 120 a SUPL RESPONSE message thatmay include the session-id, the selected positioning method, etc. (stepD).

SET 120 may obtain WLAN AP information (step E, which may occur anytime). SET 120 may then send to SLP 530 a SUPL POS INIT message that mayinclude the session-id, the WLAN AP information, and possibly otherinformation (step F). SLP 530 may determine a location estimate for SET120 based on the WLAN AP information (step G). If the location estimateis of sufficient quality, then SLP 530 may send to SET 120 a SUPL ENDmessage that may include the requested location information (step I). Ifa location estimate of sufficient quality is not obtained based on theWLAN AP information, then SLP 530 and SET 120 may exchange messages fora positioning session (step H). Upon completing the positioning session,SLP 530 may send a SUPL END message with the requested locationinformation to SET 120 (step I).

The WLAN positioning methods described herein may be supported in SUPLor X.S0024 by having new identifiers for these positioning methods inSUPL and X.S0024 and/or by enabling new location-related measurements tobe sent from terminals to SUPL or X.S0024 entities. For terminal-basedpositioning, a terminal performs measurements and computes a locationestimate. In this case, the SUPL SLP or SPC and the X.S0024 PS or PDEmay send WLAN assistance data to assist the terminal make measurementsand/or compute a location estimate. The WLAN assistance data maycomprise, e.g., location coordinates of access points, RTD values forthe OTD method, etc.

Table 2 lists signaling that may be included in OMA SUPL to support theWLAN positioning methods described herein. For the Cell ID method, cellidentity may already be included in the SUPL START and SUPL POS INITmessages but may be expanded with new parameters shown in Table 2. Thelocation-related information shown in Table 2 may also be included inother SUPL parameters and messages.

TABLE 2 WLAN Position SUPL Method Parameter SUPL Message Description APID, Positioning SUPL INIT, An identifier is used for each RTD, methodSUPL RESPONSE WLAN positioning method, OTD, e.g., AP ID, RTD, OTD, TOA,TOA, signal strength/quality, etc. and SET SUPL START, An identifier isused for each signal capabilities SUPL POS INIT WLAN positioning methodstrength/ supported by a terminal. quality Location SUPL START, ServingAP identity, e.g., ID SUPL POS INIT MAC address, IP address, etc.Location SUPL START, Serving AP location ID or new SUPL POS INITcoordinates reported by the parameter AP, e.g., from beacon frame inIEEE 802.11. Location SUPL START, WLAN technology/device ID or new SUPLPOS INIT type, e.g., 802.11b, 802.11g, parameter 802.11n, WiMAX, etc.Location SUPL START, Transmit power used by a ID or new SUPL POS INITterminal and/or an AP for parameter communication, antenna gain,received signal strength, received signal quality, etc. RTD PositioningSUPL POS (from Provide RTD measurement payload, or SET to SLP or forserving AP, RTD new SUPL SPC) measurements plus AP parameter identitiesfor other APs, etc. Positioning SUPL RESPONSE, Provide serving APlocation payload or SUPL POS (from coordinates, location new SUPL SLP orSPC to coordinates plus AP parameter SET) identities for other APs, etc.OTD Positioning SUPL POS (from Provide reference AP identity payload, orSET to SLP or (default is serving AP) new SUPL SPC) and one or moreother AP parameter identities. For each other AP identity, providemeasured OTD value between this AP and the reference AP, statistics ofmeasurement accuracy and reliability, etc. Positioning SUPL RESPONSE,Provide identities and payload or SUPL POS (from characteristics of APsthat new SUPL SLP or SPC to can be measured by a parameter SET)terminal, RTD values between identified APs, locations of identifiedAPs, etc. TOA Location ID, SUPL POS INIT, Provide absolute TOA (e.g.,positioning SUPL POS (from GPS time) for a signal from payload, or SETto SLP or serving AP and identity and new SUPL SPC) relative timing(e.g., frame parameter number) of this signal, TOAs for other identifiedsignals from other identified APs, etc. Positioning SUPL RESPONSE,Provide identities and payload or SUPL POS (from characteristics of APsthat new SUPL SLP or SPC to can be measured by a parameter SET)terminal, expected TOA values, locations of identified APs and theirabsolute timing relationship (e.g., to GPS), etc. Signal PositioningSUPL POS (from Provide signal strength and/ strength/ payload, or SET toSLP or or signal quality for the quality new SUPL SPC) serving AP,signal strengths parameter and/or qualities for other identified APs,terminal location, etc. Positioning SUPL RESPONSE, Provide locationresult payload or SUPL POS (from corresponding to signal new SUPL SLP orSPC to strength/quality for a set of parameter SET) pixels contained ina local area in which the terminal is located, etc. Cell ID Location ID,SUPL POS INIT, Provide global cell ID(s) for (e.g., for positioning SUPLPOS (from cellular networks, TA, RTD, A-GPS) payload, or SET to SLP orsignal strength/quality new SUPL SPC) measurements for each parameterprovided cell ID, etc. Positioning SUPL RESPONSE, Provide request forcell ID payload or SUPL POS (from information and indicate if new SUPLSLP or SPC to TA, RTD, signal strength/ parameter SET) qualitymeasurements are needed, etc.

The positioning payload referred to in Table 2 may be a Radio ResourceLCS Protocol (RRLP) message in 3GPP, a Radio Resource Control (RRC)message in 3GPP, a TIA-881 message in 3GPP2, etc.

In one design, a terminal/SET may send WLAN AP information to an SLP forany of the WLAN positioning methods described herein. The WLAN APinformation may be sent in a Location ID parameter or a MultipleLocation IDs parameter, which may be included in any of the SUPLmessages in Table 3.

TABLE 3 SUPL Message Description SUPL START Sent by a SET for aSET-initiated SUPL session. SUPL POS INIT Sent by a SET following a SUPLINIT message for a network-initiated SUPL session or a SUPL RESPONSEmessage for a SET-initiated SUPL session. SUPL TRIGGERED Sent by a SETto start a triggered SUPL session. START

Tables for various parameters in SUPL messages are given below. In atable for a given SUPL parameter, the first row of the table gives ashort description of the SUPL parameter. Subsequent rows give differentfields/parameters of the SUPL parameter, with each field being indicatedby symbol “>”. A given field/parameter may have subfields, with eachsubfield being indicated by symbol “>>”. In a Presence column of thetable, an “M” indicates that a field/parameter is mandatory, an “O”indicates that the field/parameter is optional, and a “CV” indicatesthat the field/parameter is conditional on value.

In one design, the Location ID parameter may include any of theinformation shown in Table 4. The Cell Info parameter may include GSMcell information, WCDMA cell information, CDMA cell information, or WLANAP information. The Status parameter may indicate the status of thecell/AP information included in the Cell Info parameter.

TABLE 4 Location ID Parameter Parameter Presence Value/DescriptionLocation ID — Describes the globally unique cell or WLAN APidentification of the most current serving cell or serving WLANAP. >Cell Info M The following cell IDs are supported: GSM Cell InfoWCDMA Cell Info CDMA Cell Info WLAN AP Info >Status M Describes whetheror not the cell or WLAN AP info is: Not Current, last known cell/AP infoCurrent, the present cell/AP info Unknown (i.e. not known whether thecell/AP id is current or not current) NOTE: The Status parameter doesnot apply to WCDMA optional parameters (Frequency Info, PrimaryScrambling Code and Measured Results List). Frequency Info, PrimaryScrambling Code and Measured Results List, if present, are alwaysconsidered to be correct for the current cell.

In one design, the WLAN AP information sent by a SET in the Cell Infoparameter of the Location ID parameter in Table 4 may include any of theinformation shown in Table 5.

TABLE 5 WLAN AP Information Parameter Parameter PresenceValue/Description WLAN AP Info — WLAN Access Point ID >AP MAC Address MAccess Point MAC Address >AP Transmit Power O AP transmit power indBm >AP Antenna Gain O AP antenna gain in dBi >AP S/N O AP S/N receivedat the SET in dB >Device Type O Options are: 802.11a device, 802.11bdevice, and 802.11g device. Future networks are permitted. >AP SignalStrength O AP signal strength received at the SET in dBm >APChannel/Frequency O AP channel/frequency of Tx/Rx >Round Trip Delay ORound Trip Delay (RTD) between the SET and AP >>RTD Value M Measured RTDvalue >>RTD Units M Units for RTD value and RTD accuracy—0.1, 1, 10, 100or 1000 nanoseconds >>RTD Accuracy O RTD standard deviation in relativeunits >SET Transmit Power O SET transmit power in dBm >SET Antenna GainO SET antenna gain in dBi >SET S/N O SET S/N received at the AP indB >SET Signal Strength O SET signal strength received at the AP indBm >AP Reported Location O Location of the AP as reported by theAP >>Location Encoding M Location encoding description LCI as per RFC3825 Text as per RFC 4119 ASN.1 as per X.694 >>Location Data M LocationData >>>Location Accuracy O Location Accuracy in units of 0.1meter >>>Location Value M Location value in the format defined inLocation Encoding

In one design, the Multiple Location IDs parameter may include any ofthe information shown in Table 6. The Multiple Location IDs parametermay include individual Location IDs for different radio access networksand may be obtained at the same time or different times.

TABLE 6 Multiple Location IDs Parameter Parameter PresenceValue/Description Multiple — This parameter contains a set of up toMaxLidSize Location ID Location ID/Relative Timestamp data. Location IDM Describes measured globally unique cell/AP identification of theserving cell/AP or cell/AP identification from any receivable radionetwork. The measured cell/AP identifications may be from differentradio access networks measured at the same time or at different times.Relative CV Time stamp of measured location Id relative to Timestamp“current location id” in units of 0.01 sec. Range from 0 to 65535*0.01sec. Time stamp for current Location Id if present is 0. The RelativeTimestamp is present if the Location ID info is historical and may beomitted if the Location ID info is current. Serving Cell M This flagindicates whether the Location ID info Flag represents a serving cell orWLAN AP or an idle (i.e., camped-on) cell or WLAN AP. If set, theLocation ID info represents serving cell or WLAN AP information. If notset, the Location ID info represents idle mode information or neighborcell or WLAN AP information.

With the features in Tables 2 through 6, an SLP may support the WLANpositioning methods described above. The SLP may also function as anetwork server for WLAN positioning methods and perform the operationsdescribed above. A SET may function as an identified/targetterminal/SET. Different or additional signaling and features may also beprovided in SUPL to support WLAN positioning methods.

Similar signaling and features may also be provided in X.S0024. AnX.S0024 PS or PDE may support the WLAN positioning methods describedabove. The PS may function as a network server for WLAN positioningmethods and perform the operations described above. A mobile station(MS) may function as an identified/target terminal.

FIG. 7 shows a design of a process 700 performed by a terminal/SET forWLAN positioning in SUPL. WLAN AP information for an access point in aWLAN and/or the SET may be determined (block 712). For block 712,measurements for signal strength, S/N, RTD, and/or some other quantitymay be obtained for the access point. Alternatively or additionally,measurements for signal strength, S/N, and/or some other quantity, whichmay be made by the access point for the SET, may be received. In anycase, the WLAN AP information may be determined based on themeasurements. The WLAN AP information may comprise any of theinformation shown in Table 5 and/or other information.

The WLAN AP information may be sent to an SLP (block 714). For anetwork-initiated SUPL session, a SUPL INIT message may be received fromthe SLP, and a SUPL POS INIT message comprising the WLAN AP informationmay be sent to the SLP, e.g., as shown in FIG. 6A. For a SET-initiatedSUPL session, a SUPL START message or a SUPL POS INIT message comprisingthe WLAN AP information may be sent to the SLP, e.g., as shown in FIG.6B. For a SET-initiated SUPL session, location information (e.g., alocation estimate for the SET) may be received from the SLP, with thelocation information being determined by the SLP based on the WLAN APinformation (block 716).

FIG. 8 shows a design of a process 800 performed by an SLP to supportWLAN positioning in SUPL. WLAN AP information may be received from a SETat the SLP (block 812). The WLAN AP information may comprise any of theinformation shown in Table 5 and/or other information. The WLAN APinformation may be received in a SUPL START message, a SUPL POS INITmessage, or a SUPL TRIGGERED START message. Location information for theSET may be determined based on the WLAN AP information (block 814). Thelocation information may be sent to the SET or a SUPL agent external tothe SET (block 816).

A terminal/SET may be capable of communicating with different radioaccess networks and/or may support different positioning methods. An SLPmay also support different positioning methods, which may or may notmatch the positioning methods supported by the SET.

FIG. 9 shows an example network deployment with different radio accessnetworks. A terminal/SET 120 may communicate with WLAN 100, a GSMnetwork 102, a WCDMA network 104, or a CDMA network 106 at any givenmoment to obtain communication services. SET 120 may receive and measuresignals from access points or base stations in the current radio accessnetwork to obtain timing measurements for the access points or basestations. SET 120 may also receive and measure signals from one or moresatellites 140 to obtain pseudo-range measurements for the satellites.

An SLP 930 may communicate with WLAN 100, GSM network 102, WCDMA network104, and/or CDMA network 106 either directly (as shown in FIG. 9) orindirectly via another network (e.g., as shown in FIG. 5). SLP 930 mayalso be part of radio access network 100, 102, 104 or 106. SLP 930 mayinclude SLC 932 and SPC 934 and may support location services andpositioning for SETs communicating with radio access networks 100, 102,104 and 106. A SUPL agent 950 may communicate with SLP 930 to obtainlocation information for SET 120.

In an aspect, an SLP may send supported network information to a SET toinform the SET of the type(s) of network measurement informationsupported by the SLP. The supported network information may be used as afilter in terms of which network measurement information the SET cansend to the SLP. The SET may send only the network measurementinformation supported by the SLP in a Location ID parameter or aMultiple Location IDs parameter to the SLP. The supported networkinformation parameter may also be used as reporting criteria for storedhistorical enhanced cell/sector measurements.

FIG. 10A shows a design of a message flow 1000 for network-initiatedlocation services in SUPL using supported network information. SUPLagent 950 may desire location information for SET 120 and may send alocation request to SLP 930 (step A). SLP 930 may authenticate andauthorize SUPL agent 950 and obtain routing information for SET 120(step B). SLP 930 may then send to SET 120 a SUPL INIT message that mayinclude a session-id, an intended positioning method, supported networkinformation, etc. (step C). SET 120 may perform a data connection setupprocedure, attach itself to a packet data network if necessary, andestablish a secure IP connection to SLP 930 (step D).

SET 120 may obtain cell or AP information for the radio access networkwith which SET 120 currently communicates (step E). SET 120 may thensend to SLP 930 a SUPL POS INIT message that may include the session-id,the cell/AP information comprising network measurement informationpermitted by the supported network information received from SLP 930,and possibly other information (step F). SLP 930 may determine alocation estimate for SET 120 based on the cell/AP information receivedfrom SET 120 (step G). If the location estimate obtained from thecell/AP information is of sufficient quality, then SLP 930 may send aSUPL END message to SET 120 (step I) and may send the requested locationinformation to SUPL agent 950 (step J). Otherwise, if a locationestimate of sufficient quality is not obtained based on the cell/APinformation, then SLP 930 and SET 120 may exchange messages for apositioning session (step H). Upon completing the positioning session,SLP 930 may send a SUPL END message to SET 120 (step I) and may send thelocation information to SUPL agent 950 (step J).

FIG. 10B shows a design of a message flow 1010 for SET-initiatedlocation services in SUPL using supported network information. A SUPLagent on SET 120 may receive a request for location information. SET 120may perform a data connection setup procedure, attach itself to a packetdata network if necessary, and establish a secure IP connection to SLP930 (step A). SET 120 may send to SLP 930 a SUPL START message that mayinclude a session-id, the SET capabilities, etc. (step B). SLP 930 maydetermine that SET 120 is currently not roaming for SUPL (step C). SLP930 may then send to SET 120 a SUPL RESPONSE message that may includethe session-id, a selected positioning method, the supported networkinformation, etc. (step D).

SET 120 may obtain cell or AP information for the radio access networkwith which SET 120 currently communicates (step E, which may occur anytime). SET 120 may then send to SLP 930 a SUPL POS INIT message that mayinclude the session-id, the cell/AP information comprising networkmeasurement information permitted by the supported network informationreceived from SLP 930, and possibly other information (step F). SLP 930may determine a location estimate for SET 120 based on the cell/APinformation received from SET 120 (step G). If the location estimate isof sufficient quality, then SLP 930 may send to SET 120 a SUPL ENDmessage that may include the requested location information (step I). Ifa location estimate of sufficient quality is not obtained based on thecell/AP information, then SLP 930 and SET 120 may exchange messages fora positioning session (step H). Upon completing the positioning session,SLP 930 may send a SUPL END message with the requested locationinformation to SET 120 (step I).

In one design, an SLP may send supported network information to a SET inany of the SUPL messages in Table 7.

TABLE 7 SUPL Message Description SUPL INIT Sent by an SLP for anetwork-initiated SUPL session. SUPL RESPONSE Sent by an SLP in responseto a SUPL START message sent by a SET for a SET-initiated SUPL session.SUPL TRIGGERED Sent by an SLP in response to a SUPL RESPONSE TRIGGEREDSTART message sent by a SET for a triggered SUPL session.

In one design, the supported network information sent by an SLP to a SETmay include any of the information shown in Table 8.

TABLE 8 Supported Network Information Parameter Parameter PresenceValue/Description WLAN M The value of this parameter is “true” or“false”. If “true”, it indicates the SET is allowed to send WLAN APinformation within the Multiple Location IDs. If “false”, the SET doesnot send WLAN AP information within the Multiple Location IDs. SupportedO This parameter provides a map of flags indicating WLAN which WLAN APinformation the SET may send Information for a current serving WLAN APin the Location ID parameter. It also indicates which WLAN APinformation the SET may send in the Multiple Location IDs parameter whenWLAN is set to “true”: AP transmit power AP antenna gain AP signal tonoise received at the SET Device type (802.11a/b/g) AP signal strengthat the SET AP channel/frequency of TX/RX Round trip delay between SETand AP SET transmit power. SET antenna gain SET signal to noise receivedat the AP SET signal strength at AP AP location as reported by AP GSM MThe value of this parameter is “true” or “false”. If “true”, itindicates the SET is allowed to send GSM information as part of LocationID within Multiple Location IDs. If “false”, the SET does not send GSMinformation within Multiple Location IDs. WCDMA M The value of thisparameter is “true” or “false”. If “true”, it indicates the SET isallowed to send WCDMA information as part of Location ID within MultipleLocation IDs. If “false”, the SET does not send WCDMA information withinMultiple Location IDs. Supported CV This parameter provides a map offlags indicating WCDMA which WCDMA network measurements the SETInformation may send for the current serving cell in the Location IDparameter. It also indicates which WCDMA network measurements the SETmay send in the Multiple Location IDs parameter when WCDMA is set to“true”: MRL (Measured Results List) CDMA M The value of this parameteris “true” or “false”. If “true”, it indicates the SET is allowed to sendCDMA information as part of Location ID within Multiple Location IDs. If“false”, the SET does not send CDMA information within Multiple LocationIDs. Historic M The value of this parameter is “true” or “false”. If“true”, it indicates the SET is allowed to send historic information aspart of Location ID within Multiple Location IDs. If “false”, the SETdoes not send historic information within Multiple Location IDs.Non-serving M The value of this parameter is “true” or “false”. If“true”, it indicates the SET is allowed to send information fornon-serving as well as serving cells and WLAN APs as part of Location IDwithin Multiple Location IDs. If “false”, the SET may only sendinformation for serving cells or serving WLAN APs within MultipleLocation IDs.

FIG. 11 shows a design of a process 1100 performed by a terminal/SET forpositioning in SUPL. Supported network information may be received froman SLP (block 1112). The supported network information may be for anytype of radio access network (e.g., WLAN, CDMA, WCDMA, GSM, etc.) andmay comprise any of the information shown in Table 8 and/or otherinformation. Network measurement information may be obtained for a radioaccess network (block 1114). Which particular network measurementinformation (or which network measurements) for the radio access networkto send to the SLP may be determined based on the supported networkinformation (block 1116). Network measurement information permitted bythe supported network information may be sent to the SLP (block 1118).

For a network-initiated SUPL session, the supported network informationmay be received in a SUPL INIT message, and the network measurementinformation permitted by the supported network information may be sentin a SUPL POS INIT message, e.g., as shown in FIG. 10A. For aSET-initiated SUPL session, the supported network information may bereceived in a SUPL RESPONSE message or a SUPL TRIGGERED RESPONSEmessage, and the network measurement information permitted by thesupported network information may be sent in a SUPL POS INIT message,e.g., as shown in FIG. 10B.

FIG. 12 shows a design of a process 1200 performed by an SLP to supportpositioning in SUPL. Supported network information may be sent from theSLP to a SET (block 1212). Network measurement information permitted bythe supported network information may be received from the SET (block1214). Location information (e.g., a location estimate) for the SET maybe determined based on the network measurement information received fromthe SET (block 1216).

FIG. 13 shows a block diagram of one access point 110, one terminal 120,and network server 130 in FIG. 1. Network server 130 may be SLP 530 inFIG. 5, SLP 930 in FIG. 9, or some other location server. Forsimplicity, FIG. 13 shows only one controller/processor 1320, one memory1322, and one transceiver 1324 for terminal 120, only onecontroller/processor 1330, one memory 1332, one transceiver 1334, andone communication (Comm) unit 1336 for access point 110, and only onecontroller/processor 1340, one memory 1342, and one communication unit1344 for network server 130. In general, each entity may include anynumber of processors, controllers, memories, transceivers, communicationunits, etc. Terminal 120 may support wireless communication with one ormore wireless networks, e.g., WLAN, GSM, WCDMA, and/or CDMA networks.Terminal 120 may also receive and process signals from one or moresatellite positioning systems, e.g., GPS, Galileo, etc.

On the downlink, access point 110 transmits traffic data, signaling, andpilot to terminals within its coverage area. These various types of dataare processed by processor 1330 and conditioned by transceiver 1334 togenerate a downlink signal, which is transmitted via an antenna. Atterminal 120, the downlink signals from one or more access points arereceived via an antenna, conditioned by transceiver 1324, and processedby processor 1320 to obtain various types of information. For example,transceiver 1324 and/or processor 1320 may make various measurements forany of the WLAN positioning methods described above. Processor 1320 mayperform process 700 in FIG. 7, process 1100 in FIG. 11, and/or otherprocesses for positioning. Memories 1322 and 1332 store program codesand data for terminal 120 and access point 110, respectively.

On the uplink, terminal 120 may transmit traffic data, signaling, andpilot to one or more access points in WLAN 100. These various types ofdata are processed by processor 1320 and conditioned by transceiver 1324to generate an uplink signal, which is transmitted via the terminalantenna. At access point 110, the uplink signals from terminal 120 andother terminals are received and conditioned by transceiver 1334 andfurther processed by processor 1330 to obtain various types ofinformation from the terminal. Access point 110 may directly orindirectly communicate with network server 130 via communication unit1336.

Within network server 130, processor 1340 performs processing for any ofthe WLAN positioning methods described above. For example, processor1340 may perform process 800 in FIG. 8, process 1200 in FIG. 12, and/orother processes to support positioning. Process 1340 may also build andmaintain databases for various WLAN positioning methods, providelocation information to terminals, compute location estimates forterminals and/or access points, etc. Memory 1342 stores program codesand data for network server 130. Communication unit 1344 allows networkserver 130 to communicate with access point 110 and/or other networkentities.

The techniques described herein may be implemented by various means. Forexample, these techniques may be implemented in hardware, firmware,software, or a combination thereof. For a hardware implementation, theprocessing units used to perform positioning at a station (e.g., aterminal, an access point, or some other entity) may be implementedwithin one or more application specific integrated circuits (ASICs),digital signal processors (DSPs), digital signal processing devices(DSPDs), programmable logic devices (PLDs), field programmable gatearrays (FPGAs), processors, controllers, micro-controllers,microprocessors, electronic devices, other electronic units designed toperform the functions described herein, a computer, or a combinationthereof.

For a firmware and/or software implementation, the techniques may beimplemented with modules (e.g., procedures, functions, etc) that performthe functions described herein. The firmware and/or software codes maybe stored in a memory (e.g., memory 1322, 1332 or 1342 in FIG. 13) andexecuted by a processor (e.g., processor 1320, 1330 or 1340). The memorymay be implemented within the processor or external to the processor.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples described herein but is to be accorded the widest scopeconsistent with the principles and novel features disclosed herein.

What is claimed is:
 1. An apparatus including a Secure User Plane Location (SUPL) Enabled Terminal (SET), the SET comprising: a processor configured to: determine access point (AP) information of an AP in a wireless local area network (WLAN); receive a SUPL message from a SUPL Location Platform (SLP), the SUPL message including one or more parameters identifying network measurement information that is supported by the SLP, the network measurement information supported by the SLP comprising one or more types of radio access networks and associated network measurement device and signal characteristic information for at least one of the one or more types of radio access networks; responsive to a determination that the one or more types of supported radio access networks includes the WLAN, and further responsive to a determination that the AP information includes the network measurement information that is supported by the SLP, filter the AP information based on the one or more parameters, the filtered AP information including only the network measurement information supported by the SLP for the WLAN; and send a second SUPL message to the SLP, the second SUPL message including the filtered AP information; and a memory coupled to the processor.
 2. The apparatus of claim 1, wherein the processor is configured to: obtain measurements for signal strength, signal-to-noise ratio (S/N), or round trip delay (RTD) for the AP, and determine the AP information based on the measurements.
 3. The apparatus of claim 1, wherein the processor is configured to: receive measurements for signal strength or signal-to-noise ratio (S/N) made by the AP for the SET, and determine the AP information based on the measurements.
 4. The apparatus of claim 1, wherein the SUPL message includes a SUPL INIT message or a SUPL RESPONSE message, wherein the second SUPL message includes a SUPL POS INIT message.
 5. The apparatus of claim 1, wherein one of the one or more parameters identifies a WLAN positioning method.
 6. The apparatus of claim 1, wherein the second SUPL message includes information that is based on transmission sequences transmitted periodically by the AP.
 7. The apparatus of claim 1, wherein the second SUPL message includes location identification information indicating one or more of AP identity, AP location coordinates, WLAN technology type, or WLAN device type.
 8. The apparatus of claim 1, wherein the second SUPL message includes a Location ID parameter or a Multiple Location IDs parameter, and wherein the Multiple Location IDs parameter includes one or more of AP Location ID information, Relative Timestamp information, and Serving Cell Flag information.
 9. The apparatus of claim 1, wherein the network measurement information includes one or more of AP transmit power, AP antenna gain, AP signal-to-noise received at the SET, device type, AP signal strength at the SET, AP channel or frequency, round trip delay (RTD) between the SET and the AP, SET transmit power, SET antenna gain, SET signal-to-noise received at the AP, SET signal strength at the AP, or AP reported location.
 10. A method of supporting Secure User Plane Location (SUPL), the method comprising: determining access point (AP) information of an AP in a wireless local area network (WLAN); receiving, by a SUPL Enabled Terminal (SET), a SUPL message from a SUPL Location Platform (SLP), the SUPL message including one or more parameters identifying a network measurement information that is supported by the SLP, the network measurement information supported by the SLP comprising one or more types of radio access networks and associated network measurement device and signal characteristic information for at least one of the one or more types of radio access networks; responsive to a determination that the one or more types of supported radio access networks includes the WLAN, and further responsive to a determination that the AP information includes the network measurement information that is supported by the SLP, filtering the AP information based on the one or more parameters, the filtered AP information including only the network measurement information supported by the SLP for the WLAN; and sending a second SUPL message to the SLP, the second SUPL message including the filtered AP information.
 11. The method of claim 10, wherein determining the AP information comprises obtaining measurements for signal strength, signal-to-noise ratio (S/N), or round trip delay (RTD) for the AP, and wherein the AP information is determined based on the measurements.
 12. The method of claim 10, wherein determining the AP information comprises receiving measurements for signal strength or signal-to-noise ratio (S/N) made by the AP for the SET, and wherein the AP information is determined based on the measurements.
 13. The method of claim 10, wherein sending the second SUPL message includes sending a SUPL POS INIT message, the SUPL POS INIT message indicating one or more of an AP identity, AP location coordinates, a WLAN technology type, or a WLAN device type.
 14. An apparatus including a Secure User Plane Location (SUPL) Location Platform (SLP), the SLP comprising: a processor configured to: initiate transmission of a SUPL message including one or more parameters identifying network measurement information that is supported by the SLP, the network measurement information supported by the SLP comprising one or more types of radio access networks and associated network measurement device and signal characteristic information for at least one of the one or more types of radio access networks, the transmission being to an SUPL Enabled Terminal (SET) in a wireless local area network (WLAN) to enable the SET to: determine that the one or more types of supported radio access networks includes the WLAN, and filter, based on the one or more parameters, access point (AP) information obtained by the SET to generate filtered AP information, the AP being in the WLAN, and the filtered AP information including only network measurement information supported by the SLP; receive a second SUPL message from the SET, the second SUPL message including the filtered AP information; and determine location information for the SET based on the filtered AP information; and a memory coupled to the processor.
 15. The apparatus of claim 14, wherein the SUPL message includes a SUPL INIT message or a SUPL RESPONSE message, and wherein the second SUPL message includes a SUPL POS INIT message.
 16. The apparatus of claim 14, wherein the processor is configured to initiate transmission of a third SUPL message to a SUPL agent external to the SET, and wherein the third SUPL message includes location information associated with a location of the SET determined based on the filtered AP information.
 17. The apparatus of claim 14, wherein the second SUPL message includes location identification information indicating one or more of an AP identity, AP location coordinates, a WLAN technology type, or a WLAN device type.
 18. The apparatus of claim 14, wherein the second SUPL message includes a Location ID parameter or a Multiple Location IDs parameter, and wherein the Multiple Location IDs parameter includes one or more of AP Location ID information, Relative Timestamp information, and Serving Cell Flag information.
 19. The apparatus of claim 14, wherein the network measurement information includes one or more of AP transmit power, AP antenna gain, AP signal-to-noise received at the SET, device type, AP signal strength at the SET, AP channel or frequency, round trip delay (RTD) between the SET and the AP, SET transmit power, SET antenna gain, SET signal-to-noise received at the AP, SET signal strength at the AP, or AP reported location.
 20. A method of supporting Secure User Plane Location (SUPL), the method comprising: transmitting, by an SUPL Location Platform (SLP), a SUPL message including one or more parameters identifying network measurement information that is supported by the SLP, the network measurement information supported by the SLP comprising one or more types of radio access networks and associated network measurement device and signal characteristic information for at least one of the one or more types of radio access networks, to an SUPL Enabled Terminal (SET) in a wireless local area network (WLAN) to enable the SET to: determine that the one or more types of supported radio access networks includes the WLAN, and filter, based on the one or more parameters, access point (AP) information obtained by the SET to generate filtered AP information, the AP being in the WLAN, and the filtered AP information including only network measurement information supported by the SLP; receiving a second SUPL message from the SET, the second SUPL message including the filtered AP information; and determining location information for the SET based on the filtered AP information.
 21. The method of claim 20, wherein the second SUPL message includes information that is based on transmission sequences transmitted periodically by the AP. 